Application Server Software

In the new wired world, servers bear much of the workload. Servers are where the business logic of e-business applications runs to provide end users with the data, services, and functions they need. It's important to make the server environment flexible. For example, you might start by offering customers access to their account information or inventory information. But, over time, you are likely to want to integrate that application with other systems in your company—for instance, a workflow application designed to escalate and resolve customer service requests and problems. 

This paper focuses on the application server software layer of the Framework that provides the core functionality for developing e-business applications. These services help businesses collaborate effectively, maintain and access information efficiently, and conduct transactions reliably in both intranet and extranet environments. They extend and enhance the Web application programming environment and provide the base on which higher-level e-business application services are built. 

The services supported in the Framework's application server software layer include the HTTP server, database and transaction services, mail and community services, collaboration services, and messaging services. The Framework enables you to start with the services that meet your immediate needs—and then add to that as your solution grows. All of these services use the Framework infrastructure, are accessible through Java^TM classes or JavaBeans, and support applications written to use the Framework programming model. These services can be integrated to build e-business solutions.

The HTTP server is the focal point for integration in the Application Framework for e-business:

• It is the entry point to server functionality supporting HTTP and IIOP requests from Framework clients.
• It supports the mechanisms for locating and invoking business logic, implemented as servlets, on the logical mid-tier server.
• It hosts the connectors that link the Web to existing enterprise applications, data, and systems.
• It coordinates, collects, and assembles Web pages composed from static and dynamic content and delivers them to Framework clients.
• It operates based on an understanding of user preferences.

The Framework's mail and community services provide the application solutions that most users and companies need in today's dynamic environment: e-mail messaging, calendaring and group scheduling, chat, and newsgroup discussions. These applications enable businesses to forge closer relationships with customers and partners, and strengthen internal teams. The Framework's community services support standard Internet technologies and protocols and are accessible from all standards-based clients. The standards supported include:

• SMTP, POP3 and IMAP4 for e-mail
• IRC for chat
• NNTP for newsgroups
• iCalendar object model and protocols for calendaring and group scheduling
• LDAP for access to directory services
• X.509 certificates for authentication

The primary focus of collaboration services is to provide a rich shared virtual workspace, and to support the coordination of business workflow processes. Collaboration services integrate information from any resource, manage what is shown to users, confer a measure of interactivity between information and the user, and manage the content through a business process in which employees, customers, and business partners can participate. The de facto standard for implementing collaborative applications is defined by the Lotus Notes API. 

Collaboration services accelerate the flow of information through an organization's decision making and approval processes. The document object store is a critical element in collaboration services:

• It contains operational data and definitions of behavior such as actions and agents, all presented as viewable documents. This enables users to define how information is presented, processed, protected, and distributed.
• It supports an integrated development environment that allows information to be retrieved and saved from transactional, application, and database systems, and it allows the user to define behavior appropriate for clients that use HTTP for browsing on the Web, for Notes clients, and other clients written to the Notes API. Additional definitions of behavior and data in the object store can be programmed with APIs expressed as Java classes and JavaBeans.
• It is optimized to efficiently distribute and manage business information of all types—tabular data (perhaps pulled from a relational database or a spreadsheet), formatted text, Web pages, graphics, links to multimedia objects such as scanned images and faxes, voice and sound, and video.
• It enables facilities such as:
• Full text search
• Document links
• Version control that tracks document changes from multiple users
• Security (at the field, document, or entire document store level)

The Framework's database services integrate the features and functions of an object-relational database with those of the base Web server. This provides a facility for managing both the operational data and multimedia content used to support intelligent decision-making within a company and to conduct business on the Internet, an intranet, or an extranet. 

The open application development environment supported by the database services

• Leverages existing business logic to build new Web-based applications
• Supports development and execution of database application programs, stored procedures and user-defined functions using the Java and JavaBeans programming model
• Provides query and update access to database information using SQL, SQLJ, and JDBC interfaces; this includes Web applications updating the database using two-phase commit
• Integrates transaction services with databases using the Open Group's XA reference model standards for integrating transaction services with databases

• Manage both traditional data (record-structured alphanumeric data) and nontraditional data (such as text, multimedia, spatial, etc.) along with user-defined data types for specialized business requirements;
• Combine the ability to define complex data types and associated functions with relational database features such as multiple views, structured query and fine-grained update concurrency;
• Store the methods and procedures for operating on data along with the data itself increasing the value and usefulness of the data by capturing its semantic content in the database. Storing operations on data along with the data also improves data integrity by promoting code; reusability and eliminating code redundancy among applications accessing the database.
• Record and enforce business policies that apply to data, for example by providing automatic validity checks.

The Framework's transaction services extend the Web server by providing a highly available, robust, expandable and secure transactional application execution environment. With these capabilities, businesses can provide new services that can expand to meet their growing markets and peak loads. Through the ability to replicate servers and distribute client load, applications can be built for any number of users, and scale to service the global demands of millions of users throughout the Internet. 

The Framework's transaction services support development and execution of both procedural and object oriented transactional application programs. Standards and capabilities supported for application use include

• Enterprise JavaBeans and Java Transaction Services (JTS), for transactional application support,
• OMG Object Transaction Services, Object Concurrency Control Service, and the full set of OMG object services,
• Open Group TxRPC for integrating transactions with RPCs and the XA reference model standards for two phase commit,
• CICS APIs.

Messaging services bring the power and flexibility of Message Oriented Middleware (MOM) to the Framework. Unlike e-mail messaging - which is concerned with the production and handling of messages that are ultimately destined for a human reader - MOM (or Business Quality Messaging as it is sometimes called) is concerned with messaging between applications. 

Messaging services allows an application to send messages to other applications, or receive messages from other applications, and provides a queuing mechanism that can reliably hold those messages, should either partner application be unavailable. The application can choose a quality of service for message delivery - messaging services will undertake to deliver each message once and only once, even in the event of system or network failure, should the application require this. A wide range of different message types can be sent: for example a message might be an application-defined request or event, a text message, a Java object, a Cobol datastructure, an interchange document for an ERP system, or a member of an industry-standard message set. 

Message services can be put to number of different uses:

• To add asynchronous processing to a web application. While many web interactions are synchronous in nature (for instance database queries), there are also many cases where application reliability and responsiveness can be improved through the use of asynchronous processing. For example when a customer places an order from a Web browser, you might wish to acknowledge receipt of the order by sending a reply to the browser before the application has completed order-processing.
• To integrate the web application with other enterprise applications and processes. In most organizations business information resides on a multiplicity of different systems (a recent survey of major organizations reported an average of 7 systems). In general these systems and the applications involved were not designed to communicate with each other - they were designed at different times by different people. Messaging services provides both the underlying transport and transformation and rules engines that allow these systems to interoperate with each other, and to be integrated via a Web application.
• To provide intercompany electronic communications, for example via an extranet. Organizations are increasingly recognizing the importance of integrating their internal systems with those of suppliers and customers (electronic value chain integration). Traditional communications are often message based, and messaging services provides reliable electronic alternative to mail or fax-based communications.

The application server software layer of the Application Framework for e-business helps businesses collaborate effectively, maintain and access information efficiently, and conduct transactions reliably in both intranet and extranet environments. The services provided in this layer extend and enhance the Web application programming environment and provide the base on which higher-level e-business application services are built. The Application Framework for e-business enables you to start with the services that meet your immediate needs—and then add to that as your solution grows.

International Business Machines Corporation 1998
IBM Corporation
Somers, NY USA
All rights reserved.

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